Conservative estimates suggest that there are at least 3.5 to 5 million Americans who are visually impaired. Bioptic systems are frequently prescribed for patients desiring increased visual acuity for reading or close work.
Eye movement disorders are experienced by many patients suffering from progressive supranuclear palsy (PSP). Some patients with other neurological diseases and/or Parkinsonism also experience vertical eye movement difficulties which make desktop functions such as reading, writing, and typing difficult or impossible. These patients are unable to turn their eyes downward due to the effects of the neurological disease. Visual field disorders such as altitudinal hemianopia are experienced by patients who are capable of vertical eye movement, but express a decrease or lack of vision in the lower half of the visual field. Both eye movement disorders and visual field disorders affect the gait and balance of the subject experiencing the visual disorder.
U.S. Pat. No. 5,452,026 to Marcy III et al., which is incorporated herein by reference, describes a vision improvement device using glasses in which one or more lenses is a rapid shutter, such as a liquid crystal shutter. The subject wears the glasses and the shutter is rapidly operated such that vision from the strong eye is subdued or blocked off long enough to allow the weak eye information to be processed by the brain to promote improved depth perception. One eye is permitted to see while the other eye is occluded. By control of the shutter, the weaker eye can be exposed for longer than the stronger eye to compensate for the brain's ability to ignore the weak eye information. As such, control over vision is described as resulting in an improved balance of per-eye information, increasing stereoscopic vision.
U.S. Pat. No. 4,279,474 to Belgorod et al., which is incorporated herein by reference, describes a spectacle lens comprising a liquid crystal layer and electrode assembly sandwiched between a pair of identically curved glass plates and layers of polarization material on the outer surfaces of the plates. The optical density of the lens is controlled by applying across the electrodes variable duty cycle voltage pulses. The duty cycle of the pulses is controlled in response to ambient light intensity measured by a photocell.
PCT Publication WO 05/043224 to Herzog et al., which is incorporated herein by reference, describes an electronically controlled, liquid-crystal eyeglass system designed for intermittent occlusion, while exercising the eyes of a user, through combined occlusion-and-exercising sessions, wherein the eyeglass system includes features to improve and monitor compliance. The system is described as having an ordinary eyeglass design, wherein the electronic components are miniaturized and hidden, having a reflective coating on the exterior surfaces of the lenses, for identical exterior appearance, even when the two lenses operate at different opacity levels. In this manner, the liquid-crystal eyeglass system does not attract attention. The liquid-crystal eyeglass system is described as being used in the treatment of amblyopia, strabismus, and a weak eye, and may be integrated with sunglasses and/or with glasses for corrective vision.
PCT Publication WO 05/051254 to Yang et al., which is incorporated herein by reference, describes a portable liquid crystal eye shield powered by a solar battery, which can adjust transmission index of light in response to the intensity of surroundings. A solar cell is mounted on a mask. The liquid crystal panel is mounted on the inner surface of a glass shield.
U.S. Pat. No. 4,601,545 to Kern et al., which is incorporated herein by reference, describes a variable lens. In one form the lens power is described as being varied and in another the power may be selectively fixed in a carrier material. There are no moving mechanical parts but instead an optically active molecular material such as liquid crystals. In one embodiment, the lens and control means for varying the power of the lens are mounted on a common substrate. A variable gradient index of refraction is achievable by applying a controlled stimulus field to the lens. For example, a geometrically configured matrix of electrical voltages, each at a selected addressable location relative to the optically active material, provides the gradient in one embodiment. A thin film embodiment finds applications in magnifying glasses, cameras, telescopes, microscopes, as well as for intraocular and contact lenses for the human eye.
U.S. Pat. No. 6,775,060 to Peli et al., which is incorporated herein by reference, describes apparatus and methods for increasing visual acuity through the use of a bioptic telescope which is at least partially embedded in a spectacle lens. In one embodiment, the telescope includes a vision lens having a vision axis and a first surface for placement substantially in front of an eye of a user. The telescope further includes a plurality of optical elements defining an optical path for viewing an object in front of the first surface. At least one of the plurality of optical elements is positioned such that at least a portion of the optical path is located within the vision lens in a plane substantially orthogonal to the vision axis.
The following patents and patent applications, which are incorporated herein by reference, may be of interest:
U.S. Pat. No. 4,756,605 to Okada et al.
U.S. Pat. No. 4,190,330 to Berreman et al.
U.S. Patent Application Publication 2006/0146275 to Metrz et al.
U.S. Pat. No. 5,552,841 to Gallorini et al.
U.S. Pat. No. 5,680,195 to Pekar et al.
U.S. Pat. No. 6,437,927 to Shafer et al.
The following articles, which are incorporated herein by reference, may be of interest:
Bowers A R et al., “Bioptic telescopes meet needs of drivers with moderate visual acuity loss,” Invest Ophthamol Vis Sci 46(1):66-74 (2005)
Peli E et al., “In-the-spectacle-lens telescopic device for low vision” Schepens Eye Research Institute, Harvard Medical School, Proceedings of SPIE Vol. 4611, Ophthalmic Technologies XII pp. 129-135 (2002)
The National Institute for Rehabilitation Engineering (NIRE), “Eyeglasses for People With Vertical Eye Movement Disorders and/or Ambulation Disorders—from PSP* or Parkinsonism (*PSP=Progressive Supranuclear Palsy). Eyeglasses for People Missing Lower Halves of Visual Fields” (2003)
Hoeft W W et al., “Amorphic lenses: a mobility aid for patients with retinitis pigmentosa,” Am J Optom Physiol Opt 62(2):142-8 (1985)